The subject of Dr Needell's restoration effort had been lying on the lawn at Nasa's Johnson Space Center (JSC) in Houston since the 1970s, and had been ravaged by its exposure to the elements.

"It was the only one in existence in which all the stages were originally intended to fly to the Moon. It was mixed and matched from stages that were intended to fly on the (cancelled) Apollo 18 and Apollo 19 missions," Allen Needell told BBC News.

"I decided that was our last and best chance to do a proper, fully documented restoration It was a complicated proposal: we had three bids, a competition, a selection committee. It took four years.

"The essential part was that we had to get it indoors. It had been outside for 27 years, and it was literally falling apart."

The Saturn V was to fly 13 times

The team developed an advanced conservation plan to preserve as much as the original material from the rocket as possible.

The fully restored rocket is now housed in a special climate-controlled building at the gate to JSC, where visitors can gawp at the scale of this gigantic achievement in 20th Century engineering.

Developed under the direction of Dr Wernher von Braun at Nasa's Marshall Space Flight Center in Huntsville, Alabama, the Saturn V was the solution to the problem of getting astronauts to the Moon.

The biggest launcher in the Saturn rocket family, it stood at a height of 111m (364ft) - taller than a 30-storey building - and could propel a payload of 48,500 kg (107,000 lb) to the Moon.

It was made up of three stages: with five powerful F-1 engines in the first stage and five J-2 engines in the second. The sleek, two-tone outer shell concealed a labyrinth of fuel lines, sensors, pumps, gauges, circuits and switches.

Some three million parts were required to function reliably, which - amazingly - they did.

"The Saturn V really was an astounding achievement. Incredibly huge, incredibly complicated and almost completely reliable," Dr Michael Neufeld, chair of the division of space history at the National Air and Space Museum in Washington DC, told BBC News.

Reg Turnill, the BBC's veteran aerospace correspondent, covered the Apollo and later the space shuttle missions from Cape Canaveral in Florida. He describes the sight of a Saturn V launch as "quite awe-inspiring".

"The press site where we were was just three miles from the launch pad," he recalls.

"On the day of the Apollo 11 launch, we saw the rocket beginning to rise. But it was between three and five seconds before the sound reached us.

"When it came it was shattering. I was quite convinced that the roof of the press stand would be brought down upon our heads. Happily, it didn't."

Dr Simon Prince, an aeronautical engineer at City University in London, says a huge step forward in engine technology was made during the development of the Saturn rockets.

The F-1 engines were themselves an incredible engineering feat

This was the ability to deal with a phenomenon called combustion instability, which could tear apart rocket thrusters. The bigger the volume of the combustion chamber in an engine, the greater a problem it was.

Soviet engineers chose to sidestep the issue by clustering lots of small engines together in order to build up thrust. But with a manned lunar landing as their goal, the Americans had to go large. And that meant tackling combustion instability head on.

A technical solution - which involved a particular configuration of the injector plate inside the engine's combustion chamber - was achieved through a process of trial and error, resulting in the destruction of numerous engines.

"The biggest form of combustion instability they could simulate inside an F-1 rocket engine was a bomb," says Dr Prince.

"So they detonated (explosive charges) inside the combustion chambers and nosecones of the F-1 engines. If they could design an engine capable of surviving a bomb explosion, it could also survive combustion instability."

Kennedy's challenge

In 1961, President John F Kennedy ignited the Moon race when he gave a speech to Congress endorsing a lunar mission by the end of the decade.

However, President Kennedy's 1970 deadline might not have been met had it not been for George Mueller.

Mr Mueller was parachuted in from the US military to become head of Nasa's office of manned space flight in 1963. He immediately ordered an independent assessment of the Apollo programme, with a realistic estimate of when the first lunar landing could be made.

When the best estimate suggested a lunar landing would not be made until late 1971, Mr Mueller took drastic action.

Wernher von Braun's engineering team at Nasa Marshall had always progressed incrementally, building and testing each new stage of a rocket before moving on to the next.

Please turn on JavaScript. Media requires JavaScript to play.

Advertisement

A close-up view of the Apollo 11 launch

"Mueller suggested they did the same as they did in the military - which was to bolt everything together and test it all at once," says Simon Prince.

This concept of "all-up testing" would cut the number of Saturn V test flights with the aim of meeting President Kennedy's end-of-the-decade target. At first, von Braun considered the idea reckless, but he was eventually won over.

"The decision was made that the first time the Saturn V was tested it would have a live first, second and third stage. There were a lot more systems that could go wrong, so nobody expected it to work properly," says Dr Prince.

"The first time that it flew, it was nearly perfect. That was testament to the devotion and skill of the Nasa Marshall engineers."

Dr Neufeld comments: "They had one launch test - the second unmanned test - where they had significant problems. But they managed to fix them in time to launch Apollo 8 to the Moon on the Saturn V's third launch."

Soviet failure

The Soviet Union had responded to President Kennedy's lunar challenge by building its own Moon rocket, called the N-1. The N-1 stood 105m (345ft) tall, with a first stage powered by 30 engines arranged in two rings.

However, the programme was underfunded and got off the blocks late. All four unmanned launches ended in catastrophic failure.

"With the N-1, the Russians again opted for a system of clustering lots of smaller engines together. That meant that if any one of them failed, it would take out all the rest, so the system reliability for the N-1 needed to be a lot better than for the Saturn V," says Dr Prince.

After the Apollo 8 astronauts entered lunar orbit in December 1968, two more Saturn V missions were required to test the lunar landing vehicle.

On 20 July 1969, the Moon race ended when Neil Armstrong stepped out of Apollo 11's lunar module and shimmied down a ladder on to the lunar surface.

Mueller (with hand over tie) and von Braun (to his left) in the firing room

But why did Nasa walk away from its most powerful and reliable rocket?

In the early to mid-1960s, there was huge optimism about the US space programme - and an incredible amount of money going into Project Apollo. According to Mike Neufeld, public support started to wane in the mid-1960s. And after the Moon landing, it crumbled to dust.

The perception that the US was behind the Soviet Union in the space race evaporated when America started making "firsts". And there were pressing concerns closer to home, such as the Vietnam War and the riots in US urban centres.

The Saturn V was terribly expensive and it was really too big for normal use

Reg Turnill, former BBC aerospace correspondent

"At the end of the 1960s, Nasa found itself in a bind. It had built this big, expensive infrastructure for manufacturing, testing and launching the Saturn V. But the public support was no longer there," says Dr Neufeld.

Though von Braun and others argued that Nasa needed the space shuttle for smaller payloads and the Saturn V as its heavy lift vehicle, financial constraints forced the space agency to make a choice between the two.

"Nasa's leadership had to make some very unpleasant decisions in the late 1960s and early 1970s The only way they could get the money to fund the space shuttle was to completely close out the Saturn-Apollo programme," explains Mike Neufeld.

Reg Turnill comments: "The Saturn V was terribly expensive and it was really too big for normal use. Once Nasa stopped going to the Moon, there was no need for all that power and that huge rocket."

Remaining Apollo flights were cancelled and the three remaining Saturn V rockets were turned into exhibition pieces.

No other flags would be planted in lunar soil after Apollo 17

The space shuttle was sold as the next breakthrough in space technology that would transform the economics of spaceflight.

"There had long been an idea that we would have to move away from throwaway rockets and go for re-useability. In doing so, we would be able to revolutionise the cost of going into space," says Mike Neufeld.

"With the shuttle, we found out that it wasn't cheaper at all. It was just as expensive as the Saturn V."

In 2004, President George W Bush unveiled a new vision for space exploration with the goal of returning astronauts to the Moon by 2020.

To many, the plans invoked as much déjà vu as awe. After more than 20 years of operations in low-Earth orbit with the shuttle, Nasa was going back to an Apollo-like system.

The Constellation programme called for the development of a new class of rockets called Ares, and a crew capsule called Orion.

"Inside, it is greatly updated, but, like Apollo, you have a conical capsule with an escape tower," says Mike Neufeld.

"Apollo is being recreated with 21st Century technology."

Nasa has been working on a new class of rockets known collectively as Ares

Whether the plan will survive the Obama administration's review of Nasa's manned space activities is unclear. The Augustine Commission, as it is called, is due to report back in August.

During the space race, the Saturn V had embodied the promise of incredible adventures in space, where humanity would spread out from the cradle to explore unfamiliar territory in the endless expanse. To many space enthusiasts today, it symbolises the lost opportunities of that hopeful age.

Invited to the grand opening of the restored Saturn V at Johnson Space Center on 20 July 2007 - the 38th anniversary of the first manned Moon landing - Apollo-era Nasa flight director Chris Kraft commented: "Each time this date rolls around, the landing of men on the Moon seems to become more surreal.

"At the time, it seemed the start of a fantastic voyage to the stars."

Time will tell whether Nasa can recapture some of that heady optimism.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.